//输入五边形的五边长和2条对角线长度，求面积

#include <stdio.h>
#include <math.h>

float area(float x,float y,float z)
{
	float s,a;
	s=(x+y+z)/2;
	a=sqrt(s*(s-x)*(s-y)*(s-z));
	return (a);
}

int main()
{
	float a,b,c,d,e,f,g,s1,s2,s3,s;
	printf("请输入5个边长:\n");
	scanf("%f %f %f %f %f",&a,&b,&c,&d,&e);
	printf("请输入2对角线长度:\n");
	scanf("%f %f",&f,&g);
	s1 = area(a,b,f);
	s2 = area(f,g,c);
	s3 = area(e,g,d);
	s = s1 + s2 + s3;
	printf("s=%.2f\n",s);

	return 0 ;
}
